$re = '/\([^-]+-(.+\.(png|jpg))\)/m';
$str = '(background_apartment_450-533c-d6072a192f2846a6d076a0d21cbae40c4901d476676ff0e24611ce199d5.png)
(background_apartment_450-533c0d6072a192f2846a6d076a0d21cbae40c4901d476676ff0e24611ce199d5.jpg)
background_apartment_450-533c0d6072a192f2846a6d076a0d21cbae40c4901d476676ff0e24611ce199d5.jpg
(background_apartment_450-533c0d6072a192f2846a6d076a0d21cbae40c4901d476676ff0e24611ce199d5)';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php